In the morning

Page 3 of methods of flood estimation pdf

Methodology of flood estimation

I probably should have a wider list of design flood estimation methods in the hydro_extremes lecture

Field intuition and modelling

Conceptual view of my PhD catchment

Electrical conductivity: natural tracer

Initial data and modelling results

Two component mixing model

  • Write the water balance to express \(Q(t)\), the total discharge at time t, as a function of \(Q_{gw}(t)\), the groundwater exfiltration and \(Q_{gl}(t)\), the glacier melt contribution (we neglect rain and evapotranspiration)
  • \(Q(t) = Q_{gw}(t) + Q_{gl}(t)\)
  • Write the solute mass balance to express \(Q(t) EC(t)\) (the mass of solutes exiting the catchment per second) as a function of \(Q_{gw}(t)\), \(Q_{gl}(t)\) as well as \(EC_{gw}\) and \(EC_{gl}\), which are respectively the constant electrical conductivity values for groundwater and glacier melt. EC is a proxy for the concentration of solutes in water.
  • \(Q(t) * EC(t) = Q_{gw}(t)*EC_{gw} + Q_{gl}(t)*EC_{gl}\)

Total discharge as a function of \(Q_{gw}(t)\)

  • By substituting \(Q_{gl}(t)\) in one of the previous equations, express \(Q(t)\) as a function of \(Q_{gw}(t)\), \(EC(t)\) and the constants \(EC_{gw}\) and \(EC_{gl}\)
  • \(Q(t) = \frac{Q_{gw}(t)*(EC_{gw} - EC_{gl})}{EC(t) - EC_{gl}}\)

Modelled baseflow recession

Aquifer recharge with snowmelt

Mass balance verification for the infiltration rate

  • Write the infiltration rate as a function of the storage volume and the exfiltration rate \(Q_{gw}\)
  • We neglect evapotranspiration and recharge from rain
  • \(Q_{inf}(t) = dV(t)dt + Q_{gw}(t)\)

Seasonaly variable GW contribution

Climate change PhD example

Climate change impacts

  • Remember what “downscaling” is?
  • Downscaling adds small-scale details, like topography-induced variations, which are not seen on the GCMs larger grid
  • Which parameters are affected?
  • Air temperature
  • Precipitation
  • Relative humidity
  • Wind speed
  • Wind direction